It all depends for what reason you'd want to read, 'I Know Why the Caged Bird Sings'? Do I care about the troubled times and hard life of Maya Angelou? Not so much. The reason I read the book and refer to it often is because the lady is one of the purist writers I've come across. She could do in one sentence what GRRM and other popular writers accomplish in pages of bloated melodrama. The lady knew how to put emotions into words.
Yes, it is an excellent read. I'm not much for autobiography but it is beautifully written. Her ability to use language is inspiring. Worthwhile? Most definately!